Multifocal Electroretinogram Findings after Intravitreal Bevacizumab Injection in Choroidal Neovascularization of Age-Related Macular Degeneration

PURPOSE: To evaluate the changes in multifocal electroretinogram (mfERG) and optical coherence tomography (OCT) after intravitreal bevacizumab injection in the treatment of age-related macular degeneration (AMD). METHODS: Twenty-one eyes with choroidal neovascularization secondary to AMD were studied before and after intravitreal bevacizumab injection for best corrected visual acuity (BCVA), OCT, and mfERG. RESULTS: The BCVA improved, while central macular thickness and total macular volume in OCT decreased after intravitreal bevacizumab injection (p = 0.03, 0.01, and 0.01, respectively). In mfERG, the amplitude of P1, and implicit time of P1 and N1 indicated a statistically significant improvement of retinal response after intravitreal bevacizumab injection. CONCLUSIONS: There is a potential role for mfERG in evaluating the effect on retinal function of intravitreal bevacizumab injection.

Use of Spectral-Domain Optical Coherence Tomography to Analyze Macular Thickness According to Refractive Error

PURPOSE: To investigate the correlation of macular retinal thickness and refractive error using spectral-domain optical coherence tomography (SD-OCT). METHODS: A total of 120 eyes with no posterior abnormalities were enrolled in the present study. Subjects were divided into 3 groups based on their spherical equivalent. Visual acuity, refraction, slit lamp examination, tonometry and fundus examination were performed. Retinal thickness between the RPE and IS/OS junction was measured at the fovea, 1 mm (inner ring) and 2 mm (outer ring) superiorly, inferiorly, nasally and temporally using SD-OCT. Overall average thickness, average foveal thickness, and the inner and outer ring macular thickness were measured. RESULTS: The average foveal thickness was significantly greater in the high myopic eyes than in the low to moderate myopic and emmetropic eyes (p = 0.001). However, the RPE-IS/OS junction thickness of the foveola and the outer macular thickness were significantly lower (p = 0.001, p = 0.002) in the high myopic eyes. There was a weak, but significant negative correlation between refractive error and average foveal thickness (r = -0.38, p = 0.001). A positive correlation was found between refractive error and the RPE-IS/OS junction thickness (r = 0.40, p = 0.001). CONCLUSIONS: Macular retinal thickness is related to refractive error in normal subjects. Effects of eyeball elongation are more apparent in high myopic eyes than in low to moderate myopic eyes. A significant decline in the RPE-IS/OS junction thickness suggests the photoreceptor outer segments in the foveola are damaged in high myopic eyes.

Evaluation of the Central Macula in Commotio Retinae Not Associated with Other Types of Traumatic Retinopathy

PURPOSE: To report on the anatomical and functional changes to the macula in nine patients suffering from commotio retinae not accompanied by any other types of traumatic retinopathy. METHODS: Nine injured eyes with commotio retinae were evaluated soon after ocular trauma with ophthalmic examination, including Spectral-domain optical coherence tomography (SD-OCT). In 12 eyes of 6 patients, Humphrey visual field (HVF) and multifocal electroretinogram (mfERG) were performed. Re-examinations were periodically performed for a mean of 26 days. Data from 9 injured eyes were collected and compared to data collected from the 9 non-affected eyes of the same patients. RESULTS: SD-OCT revealed no significant differences in the foveal thickness and total macular volume between traumatized and intact eyes in all 9 patients. Only 3 out of the 9 injured eyes showed abnormal findings in SD-OCT images such as discontinuity of the inner/outer segment (IS/OS) junction or abnormal hyper-reflectivity from the IS/OS and retinal pigment epithelium (RPE) lines in the macula. HVF and mfERG results did not show any functional deterioration in the injured eyes compared with intact eyes. During follow-up, the commotio retinae resolved in all 9 eyes. The changes to the outer retinal region detected in 3 patients by SD-OCT were also resolved. CONCLUSIONS: Acute retinal changes in commotio retinae, not associated with other retinal pathologies, were resolved without histological and functional sequelae. In a few cases of commotio retinae, SD-OCT revealed transient abnormalities mainly observed at the IS/OS and RPE complexes.

A Clinical Applications of Photopic Negative Response (PhNR) for the Treatment of Glaucoma and Diabetic Retinopathy

PURPOSE: To determine the clinical utility of using photopic negative response (PhNR) by comparing the parameters for normal, primary open angle glaucoma (POAG) and diabetic retinopathy (DR). METHODS: Electroretinography (UTAS E-3000) was performed in 12 normal, 12 POAG, and 12 DR subjects. Amplitudes and implicit times for PhNR were compared among the three groups. The mean deviation (MD) and pattern standard deviation (PSD) were evaluated using standard automated perimetry (SAP). The mean retinal nerve fiber layer (RNFL) thickness and cup-disc ratio were measured using optical coherence tomography. RESULTS: The a-waves and b-waves were not different among the three groups. However, compared to normal subjects, the PhNR amplitudes were reduced, and the PhNR implicit times were prolonged in the POAG and DR patients (p<0.001, p<0.001). The MD and RNFL thickness were correlated with the amplitudes and implicit times for the PhNR. CONCLUSIONS: PhNR may be useful for the detection of inner retinal dysfunction, which is seen in patients who have glaucoma or diabetic retinopathy.

Electrophysiological and Morphological Changes After Intravitreal Bevacizumab Injection with Macular Edema or Choroidal Neovascularization

PURPOSE: To evaluate the functional and anatomical statuses of macula with multifocal electroretinogram (mfERG) and optical coherence tomography (OCT) for the treatment of patients with macular edema after intravitreal bevacizumab injection. METHODS: Patients were injected with intravitreal bevacizumab (1.875 mg/0.075 ml) for macular edema with choroidal neovascularization (CNV), diabetic retinopathy and retinal vein occlusion. RESULTS: A total of 120 eyes (96 patients) were diagnosed with diabetic retinopathy, CNV with age-related macular degeneration and retinal vein occlusion. Visual acuity improved from logMAR 0.85+/-0.39 to 0.54+/-0.38 after intravitreal bevacizumab injection. The implicit time of P1 and N2 in mfERG decreased, and the amplitude of P1 showed a statistically significant increase. Central macular thickness decreased from 374.4+/-135.2 micrometer to 249.0+/-72.0 micrometer. CONCLUSIONS: After intravitreal bevacizumab injection, functional and anatomical statuses of mfERG and OCT improved. This study demonstrates a method for utilizing mfERG to assess the effectiveness of treatments such as bevacizumab.

Comparison of Corneal Thickness and Anterior Chamber Depth Measured With Orbscan, Pentacam, and Ultrasound Pachymetry

PURPOSE:We compared the measurements of corneal thickness and anterior chamber depth (ACD) using three different methods Orbscan, Pentacam and ultrasound pachymetry. METHODS: In healthy volunteers, central corneal thickness was measured with Orbscan, Pentacam and ultrasound pachymetry. Estimation of peripheral corneal thickness and ACD were done by Orbscan and Pentacam. All results were compared statistically. RESULTS: The mean central corneal thickness of 64 eyes measured by Orbscan, Pentacam and ultrasound pachymetry were 509.1+/-61.0 microm, 539.2+/-51.7 microm and 527.4+/-48.3 microm, respectively. There were statistically significant differences in the results among the three methods (repeated-measures analysis of variance (ANOVA), p0.90, p<0.05). The temporal and nasal peripheral corneal thicknesses were thinner in the Pentacam than in the Orbscan (paired t-test, p<0.05). The superior and inferior corneal thickness and ACD were not significantly different. CONCLUSIONS: The results of the three instruments have significant correlations with each other, so all methods are clinically useful.

10-Prism-Diopter Fixation Test for Amblyopia

PURPOSE: To evaluate the clinical usefulness of the 10-prism-diopter (PD) fixation test in the diagnosis of amblyopia. METHODS: The study comprised 132 children (42 normal, 90 amblyopes) who underwent the 10-PD fixation test and stereoacuity test. The sensitivity, specificity, false-positive and false-negative rates of the 10-PD fixation test were analyzed according to the clinical diagnosis. RESULTS: The 10-PD fixation test sensitivity was 86%, the specificity was 61%, the false-positive rate was 17% and the false-negative rate was 24%. Data showed agreement between the 10-PD fixation test and the stereoacuity test (gamma=0.737, p=0.000). The results in the 10-PD base-down test and base-out test also showed agreement (gamma=0.779, p=0.000). CONCLUSIONS: The 10-PD fixation test is a simple and useful method in detecting amblyopia.

The Focal Aggravation of the Macular Edema on Optical Coherence Tomography After Intravitreal Triamcinolone Injection

PURPOSE: To evaluate the relationship between focal aggravation of the macular edema on retinal thickness change analysis (RTCA) of optical coherence tomography (OCT) and fluorescein angiographic findings in patients after an intravitreal triamcinolone injection (IVTA). METHODS: From May 2004 to April 2005, RTCA in a fast macular thickness map (FMTM) of OCT was performed before and 4 weeks after IVTA in patients who had macular edemas caused by diabetic retinopathy and retinal vein occlusion. Patients underwent IVTA, and focal aggravation of the edema was detected. After overlapping the OCT findings onto angiographic pictures, the relationship between the focal aggravation on OCT and the leaking point on angiography was investigated. RESULT: In the patient group, focal aggravation was found in 5 of 27 eyes (18.5%); in the control group, only 2 of 30 eyes (6.7%) showed focal aggravation. As compared with angiographic pictures, 4 eyes with focal aggravation showed no relation to the leakage on angiography. CONCLUSIONS: Focal aggravation of macular edemas after IVTA on RTCA are not related to the leakage on angiography and could be an error from several artifacts.

The Effect of Intracameral Triamcinolone Acetonide Injection on the Cornea in Rabbits

PURPOSE: To evaluate the safety and effects of intracameral triamcinolone acetonide injection in rabbit corneas. METHODS: Triamcinolone acetonide in the amounts of 0.5, 1, and 2 mg was injected into the anterior chamber of rabbit eyes, and intraocular pressure, corneal thickness, and endothelial cell counts were evaluated on days 1, 3, 7, 14, and 28. Twenty-eight days after triamcinolone acetonide injection, the eyes were enucleated and examined after TUNEL staining. RESULTS: No statistically significant differences were found among control, 0.5, and 1 mg triamcinolone-injected eyes in central corneal thickness, endothelial cell density, pleomorphism, and polymegathism. There was no difference between 2 mg triamcinolone-injected eyes and control eyes for corneal thickness and cell density, but there were statistically significant differences between these two groups for pleomorphism (p<0.05) and polymegathism (p<0.05). CONCLUSIONS: The results of this study suggested that intracameral injections of 0.5~1 mg of triamcinolone acetonide are beneficial and cause no toxic effects on corneas.

Distribution and Study on Single Nucleotide Polymorphism (SNP) of spvR Gene in Korean Isolates of Salmonella / 감염과화학요법

BACKGROUND: The Salmonella virulence plasmid (spv) genes (spvR, A, B, C and D) on the large virulence plasmids of pathogenic Salmonella serotypes can replace the virulence of the whole plasmid. Recently, virulence plasmid-negative pathogenic Salmonella isolates were isolated. However, positive rates of spv genes among Korean Salmonella serotypes have been obscure. spv genes are conserved in compared to other virulence genes but there are single nucleotide polymorphisms (SNPs) conserved in only certain serotype. Such SNPs are useful for differentiation and understanding evolution of certain serotypes. MATERIALS AND METHODS: Salmonella serotypes isolated from live stocks [Salmonella typhimurium (ST, 26), S. enteritidis (SE, 10), S. gallinarum (SG, 40) and S. pullorum (SP, 53)] were used for colony-PCR. A primer set covering single nucleotide polymorphism (SNP) at 625th nucleotide of spvR was designed. The nucleotide sequences of amplicons were determined by cyclic sequencing method and RFLP was performed by using MseI. RESULTS: All isolates of SE, SG and SP, including four plasmid-negative isolates, showed specific amplicons but not all of ST (19/26, 73%) were positive to spvR. Based on the nucleotide sequence of 625th nucleotide and PCR-RFLP, SE, SG and SP [A(625)] and ST [G(625)] could be differentiated. CONCLUSION: spvR can be used as a molecular marker to detect virulent SE, SG, SP and the SNP may be useful for differentiation of SE, SG, SP and ST. According to the SNP study SE may be evolutionarily closer to SG and SP than ST.

Distribution and Study on Single Nucleotide Polymorphism (SNP) of spvR Gene in Korean Isolates of Salmonella / 감염과화학요법

BACKGROUND: The Salmonella virulence plasmid (spv) genes (spvR, A, B, C and D) on the large virulence plasmids of pathogenic Salmonella serotypes can replace the virulence of the whole plasmid. Recently, virulence plasmid-negative pathogenic Salmonella isolates were isolated. However, positive rates of spv genes among Korean Salmonella serotypes have been obscure. spv genes are conserved in compared to other virulence genes but there are single nucleotide polymorphisms (SNPs) conserved in only certain serotype. Such SNPs are useful for differentiation and understanding evolution of certain serotypes. MATERIALS AND METHODS: Salmonella serotypes isolated from live stocks [Salmonella typhimurium (ST, 26), S. enteritidis (SE, 10), S. gallinarum (SG, 40) and S. pullorum (SP, 53)] were used for colony-PCR. A primer set covering single nucleotide polymorphism (SNP) at 625th nucleotide of spvR was designed. The nucleotide sequences of amplicons were determined by cyclic sequencing method and RFLP was performed by using MseI. RESULTS: All isolates of SE, SG and SP, including four plasmid-negative isolates, showed specific amplicons but not all of ST (19/26, 73%) were positive to spvR. Based on the nucleotide sequence of 625th nucleotide and PCR-RFLP, SE, SG and SP [A(625)] and ST [G(625)] could be differentiated. CONCLUSION: spvR can be used as a molecular marker to detect virulent SE, SG, SP and the SNP may be useful for differentiation of SE, SG, SP and ST. According to the SNP study SE may be evolutionarily closer to SG and SP than ST.

Characterization of lymphocyte subpopulations and major histocompatibility complex haplotypes of mastitis-resistant and susceptible cows

Bovine mastitis is an infectious disease with a major economic influence on the dairy industry worldwide. Many factors such as environment, pathogen, and host affect susceptibility or resistance of an individual cow to bovine mastitis. Recently, there has been considerable interest in defining genetic and immunological markers that could be used to select for improved disease resistance. In this study we have analyzed the lymphocyte subpopulations of mastitis-resistant and susceptible cows using monoclonal antibodies specific for bovine leukocyte differentiation antigens and flow cytometry. We have also used a microarray typing technique to define the bovine leukocyte antigen (BoLA) class I and class II haplotypes associated with resistance or susceptibility to bovine mastitis. A striking finding of the present study is that susceptibility to mastitis was associated with major histocompatibility complex (MHC) haplotypes that have only a single set of DQ genes. The study also revealed that susceptible cows had CD4:CD8 ratios of less than one in both their mammary gland secretions and peripheral blood. These results raise the possibility that the number of DQ genes that a cow has and/or a cow's CD4:CD8 ratio could be used as indicators of susceptibility to bovine mastitis.

Biochemical, Serological and Virulence-associated Characteristics of Yersinia enterocolitica Isolated in Korea / 감염

BACKGROUND: Yersinia enterocolitica is an inhabitant in lower intestinal tract of many domestic and wild animals as well as in nature. Of the several forms of diseases by Y. enterocolitica, acute enteritis, especially in young children, is most common. Infection of the bacteria is usually occurred through fecal-oral route by contaminated foods or water, especially mountainspring water. Therefore, we isolated Y. enterocolitica from feces of pigs and mountainspring water and investigated the biochemical, serological, genetical and virulence-associated characteristics of the bacteria for the epidemiological analysis. METHODS: Fifty-one strains of Y. enterocolitica were isolated from the samples and identified by biochemical tests and VITEK system. We performed antimicrobial susceptibility test, in vitro virulence-associated characteristics, biotyping, serotyping, and PCR-ribotyping and compared the methods, such as biotype, serotype and PCR-ribotyping, to differentiate the isolates. RESULTS: Biochemical properties of the isolates were very similar to those of reference strains. They were susceptible to chloramphenicol, tetracycline, norfloxacin, but resistant to bacitracin, ampicillin in antimicrobial susceptibility test. In vitro virulence-associated tests, the positive strains were 27 isolates (52.9%) in CRMOX+, 10 isolates (19.6%) in CV+, 30 isolates (58.8%) in CD+, 20 isolates (39.2%) in esculin+ and 20 isolates in salicin+ (39.2%). Thirty-one strains of 51 isolates (61%) harbored about 70 kb plasmid presumably associated with virulence factor. Biotypes and serotypes of the strains were 3B, 3A, 4 and O:3, O:13, O:16 in order, respectively. Type I having 700 and 800 bps products was the most common type of PCR-ribotypes. CONCLUSION: Biochemical properties, biotypes and serotypes of the isolates were similar with previously reports in Korea. PCR-ribotyping, a genetical method, could be a more effective tool for differentiating isolates of Yersinia enterocolitica than conventional methods such as serotype, biotype.